Abstract: Deep excavation often results in surface subsidence, groundwater level fluctuations, and structural stability concerns, which can compromise the safety of adjacent infrastructure and the surrounding environment. While previous studies have explored excavation-induced effects, a comprehensive understanding of the applicability of recharging measures in complex soil conditions remains lacking, particularly regarding deformation control mechanisms and the impact of waterproof curtain damage on recharging performance and soil response. This study investigated a foundation pit project adjacent to a high-speed railway in Yancheng, Jiangsu Province. Integrating field monitoring, in-situ recharge tests, and numerical simulations, it assessed the environmental effects of groundwater recharge in phreatic and confined aquifers beyond the waterproof curtain under multilayer soil conditions. Additionally, the influence of curtain damage on soil deformation and recharging efficiency was discussed. The results show that the combined waterproof curtain and recharging system control surface subsidence effectively, with railway foundation settlement fluctuations remaining below 2.0 mm, well within safety thresholds. Damage to the upper curtain induces a maximum pit uplift of 0.29 mm, approximately double that caused by damage to the lower curtain. Curtain defects alter groundwater pathways and flow dynamics, allowing recharge water to penetrate beneath the pit and intensify basal uplift. Recharge schemes should be holistically optimized to balance settlement control and water demand, ensuring environmental safety. The study offers valuable technical insights for the design and optimization of recharging measures in deep excavation projects.